Transmitting or receiving aerial system for wireless telegraphy or telephony



"Sept. 1 1931 c s. FRANKLIN 1,321,330

TRANSIEITTING OR RECEIVING AERIAL SYSTEM FOR WIRELESS TELEGRAPHY ORTELEPHONY Original Filed Feb. 17 1925 0 o 2 o W, O C 0 0 C2 "'7 Qvwntoz4 CHARLES S. FRANKLIN Patented Sept. 1, 1931 UNETED STATES PATENT OFFICECHARLES SAMUEL FRANKLIN, OF BUCKHURST HILL, ENGLAND, ASSIGNOB TO RADIOCORPORATION OF AMERICA, A CORPORATION OF DELAWARE- TRANSMITTING ORRECEIVING AERIAL SYSTEM FOR WIRELESS 'TELEGBAPHY OR TELEPHONYApplication filed February 17, 1926, Serial No. 88,761, and in GreatBritain February 24, 1925. Renewed January 31, 1931.

This invention relates to improvements in transmitting or receivingaerial systems for wireless telegraphy or telephony.

It is known that if an .aerial is placed at the focus of a parabolicreflector which is formed of a number of vertical wires, then aconcentration of energy takes place and the electromagnetic waves areprojected in the form of a beam, thedegree of concentration beinglargely determined by the size of the reflector relative to the wavelength.

I have described in British specification No. 128665, July v3, 1919, howimproved results can be obtained by making the reflector of a number oftuned wires placed one above the other.

Unless such a reflectorbe very large in both directions, relative to thewave length, it is not possible to obtain a very high degree ofconcentration.

Consider, for instance, a reflectingsystem made of a number of rodsapproximately wave length long, arranged as aparabolic cylinder about anaerial at the focus. As

1 the parabola is extended by adding rods, the

aperture of the parabola is increased and a greater degree ofconcentration results. It is obvious, however, that as the distance ofthe reflecting rods from the focus increases, so the percentage ofenergy radiated from the aerial in that direction which is reflected bythe reflecting rod becomes smaller and smaller. In practice a limit issoon reached beyond which no appreciable improvement is obtained byfurther increasing the aperture of the reflector. I

According to this invention I provide two or more parabolic reflectors,arranged on a line at right angles to the axis of each reflector, sothat their axes are parallel, or substantially so, to one another. Ifthe oscillations fin-the .aerials at the focusof each reflector 'bemaintained in phase, then the reflectors act together, resulting in aneffective concentration proportional to the combined apertures of allthe reflectors, without loss of efficiency.

This method of using a number of parabolic reflectors side by side,makes it possible to obtain concentration of the energy substantiallyproportional to the total apertures.

thus be obtained by employing the requisite number of parabolicreflectors, and such concentration may exceed that which is practical toobtain from a single parabolic reflector of the same aperture.

The oscillations in the aerials at the focus of each reflector may bemaintained-in phase with each other by being fed through a cable systemfrom a common transmitter.

The cables to each aerial should have equiva The aerials A1 and A2 arepreferably ofthe type described in my application No. 47232 filed July31, 1925, but they may be simple aerials and may be earthed, or thewhole system of aerials and reflcctorsmay be arranged at a height abovethe ground.

High frequency energy is conveyed to the aerials by means of feedingwires or cables F1, F2 and F3. C1 and C2 are coils sit uated at the endsof the feeders F1 and F2, and are coupled to the aerials A1 and A2. Thedegree of coupling to the aerials should be equal and for the bestefliciency should be such that no reflections take place along F1 andF2. The feeders F1 and F2, which should be electrically equal to eachother, are connected through a transformer T to the feeder F3 whichconveys the high frequency energy from the high frequency generatorwhich may be located in any convenient position. The transformer T ispreferably adjusted so that no reflections take place from this pointback along the feeder F3. I I

If the conditions are correctly fulfilled,

Any desired degree of concentration can CJI then the high frequencyoscillations produced in the aerials A1 and A2 will be in phase with oneanother, and the waves emitted by the two para-bolic'systems will acttogether so as to produce in the desired direction a concentration ofenergy substantially proportional to the sum of the apertures of theseparate reflectors.

Any number of separate reflectors may be combined in the mannerdescribed above for two reflectors, while such a system of combinedreflectors may be utilized for reception as well as for transmission.

Having described my invention what I claim is:

1. A directional aerial system comprising a plurality of parabolicreflectors arranged side by side, with substantially parallel axis, andan aerial at the focus of each reflector, all of the aerials beingmaintained in the same phase so that a directional concentration ofenergy is obtained.

2. A directive aerial system comprising a plurality of parabolicreflectors arranged side by side, an'aerial at the focus of each'reflector, all of the focal aerials being maintained in the same phaseso that the concentration of energy radiated is substantiallyproportional to the sum of the apertures of the reflectors.

3. A directional aerial system comprising aplurality of parabolicreflectors arranged on'a line at right angles to the axis of eachreflector, so that their axes are substantially parallel to one another,and an aerial located at the focus of each reflector,

each aerial being maintained in the samephase so that a directiveconcentration of energy is obtained. 4. A directive aerial systemcomprising a plurality of parabolic reflectors, each reflector having anaerial. at its focus, all the focal aerials being maintained in the,same phase so that a'directional concentration of energy is obtained,and a common means to excite said aerials.

5. A directive aerial system comprising a plurality of parabolicreflectors, each reflector having an aerial at its focus, all the focalaerials being maintained in the same phase so that a directionalconcentration of energy is obtained, and a common means to excite saidaerials, comprising a transmission line so arranged as to preventreflection of the energy passing through it.

6. A directive aerial system comprising a plurality of reflectorsarranged on a straight line at right angles to the center line of eachreflector, each reflector comprising a plurality of conductors arrangedon a curve, an aerial on the center line of each reflector, and means toexcite said aerials in predetermined phase relationship.

7. In a directive aerial system a plurality of cylindrical parabolicreflectors located adjacent each other, said reflectors each beingcomposed of a plurality of spaced tuned wires or rods, an aerial locatedat the focus of each reflector, and a single means to excite saidaerials in a predetermined phase relation.

7 8. In a directive aerial system, a plurality of primary aerialslocated adjacent each other, tuned reflecting means associated with eachof said primary aerials, said tuned reflecting means comprising aplurality of conductors arranged on a curve, and non-reflective meansfor feeding energy to said primary aerials.

9. A directive. aerial system comprising a plurailty of associatedparabolic reflectors, each reflector having an aerial consist ing of alinear conductor at its focus, all the focalaerials beingmaintained inthe same phase so that a directional concentration of energy isobtained.

'10. In a directive aerial system a plurality of associated parabolicreflectors, composed of a plurality of spaced tuned wires'or rods, anaerial located at the focus of each reflector, and inductance coilcoupled. to each of said aerials, feelers connected to each of saidcoils, a transformer connected to said feeders and means to feed highfrequency oscillations to said transformer.

11. In a directive aerial system a plurality of parabolic reflectors,composed of a plurality of spaced tuned wires or rods, an aerial locatedat the focus of each reflector. and inductance coil coupled to each ofsaid aerials, feeders of equal electrical length connected to each ofsaid coils, a transformer connected to said feeders and non-reflectivemeans to feed high frequency oscillations to said transformer.

12. In a directive aerial system a plurality of parabolic reflectors,composed of a plurality of spaced tuned wires or rods, an aerial locatedat the focus of each reflector. and inductance coil coupled to each of.said aerials, feeders connected to each of said coils, a transformerconnected to said feeders and means to feed high frequency oscillationsto said transformer, said feeds ers and said transformer being soarranged that no reflection takes place therefrom.

13. In a directive aerial system, a plurality of adjacent symmetricalcurved reflectors, each reflector comprising a plurality of tunedconductors, an aerial located on the axis of symmetry of each reflect-orand common non-reflective means to excite each of said. aerials inpredetermined phase relation.

14. In a directive aerial system, a plurality of symmetrical reflectorseach comprising a plurality of conductors arranged on a curve, saidreflectors located on a line perpendicular to their respective axes ofsymmetry, a focal aerial located on each axis, and common inductivemeans for energizing said aerials.

15. In a communication system for the transmission or reception ofelectromagnetic Wave energy, a plurality of independent radiant systems,each system comprising a primary antenna and a reflector partiallyenclosing the antenna, said systems being placed adjacent each other ona straight line substantially perpendicular to the desired direction ofradiant action.

16. In combination, in radio signaling apparatus utilizingelectromagnetic Wave phenomena, a plurality of independent, physicallyseparated radiating systems, each independent system comprising aradiating antenna and a reflector therefor, each reflector comprising aplurality of conductors spaced apart in a direction transverse to theirlongitudinal dimension, said systems being arranged on a straightsubstantially horizontal line such that their independent radiationcharacteristics are substantially parallel in a substantially horizontalplane.

17. In combination, in a communication system utilizing electromagneticWave phe nomena, a plurality of physically separated radiant responsivesystems arranged on a straight substantially horizontal line in afashion such that their radiant characteristics are substantiallyparallel in substantially a horizontal plane, each radiant responsivesystem comprising a primary oscillating system and a reflectorcomprising a plurality of oscillators parallel to the primaryoscillating system, and means coupling each primary oscillating systemto high frequency apparatus whereby the action of the combined radiantresponsive systems results elfectively in a sharper char-.

acteristic in a substantially horizontal plane than the characteristicof each radiant responsive system taken independently.

CHARLES SAMUEL FRANKLIN.

